1. Technical Field
The present invention relates to a polarization controller, a projector system, a polarization control method and an image control method, for a three-dimensional image display.
2. Related Art
In the related art, a three-dimensional image display system that stereoscopically displays a display image as a three-dimensional image has been proposed (for example, see JP-A-2009-122430).
A polarized 3D system has been known as a method of stereoscopically displaying the display image as the three-dimensional image.
According to the polarized 3D system, two parallax images having different polarization directions from each other are projected by a liquid crystal projector (hereinafter, referred to as a 3D (three-dimensional) projector) or the like corresponding to the three-dimensional image display, and the two parallax images are divided by polarized glasses or the like so that the polarization directions are different from each other, to divide the image between the right eye and the left eye (for example, see JP-A-2009-122430). In viewing the display image with the polarized 3D system, light for an image to be viewed by a viewer is transmitted in the order of the 3D projector, the polarization controller, a screen and the polarization glasses.
That is, if projection lights for the parallax images are output from the 3D projector, the polarization controller polarizes the projection lights. For example, in a case where the projection lights are linearly polarized lights, the polarization controller polarizes the projection light for a right-eye image into a left-handed circularly polarized light and polarizes the projection light for a left-eye image into a right-handed circularly polarized light.
Then, the projection lights of the respective circularly polarized lights are projected onto the screen, and reflected lights enter the eyes of the viewer through the polarization glasses, in which the polarization directions of right and left glasses are different from each other, which are worn by the viewer. Then, the viewer views a three-dimensional image by the parallax images that enter the right eye and the left eye.
The 3D projector disclosed in the above-mentioned JP-A-2009-122430 or the like is capable of performing a simple front projection in which the viewer views images projected on the screen through the polarization glasses and also a rear projection in which the viewer views images projected on a rear surface of the screen from a front surface of the screen.
Further, in the case of any projection, in a case where the distance between the polarization controller and the screen does not correspond to a straight line due to a problem or the like of the structure of a room, the projection lights output from the polarization controller are reflected once or plural times by a reflection mirror and are projected onto the screen, so that the viewer views the images using the polarization glasses.
Here, as described above, for example, in a case where, in the projection lights projected on the screen, the projection light for the right-eye image is set as the right-handed circularly polarized light and the projection light for the left-eye image is set as the left-handed circularly polarized light, the polarization directions of the respective projection lights are horizontally reversed due to reflection on the screen (due to phase reversal caused by mirror reflection). For example, the polarization glasses have a configuration corresponding to one-time reflection, in which a left eye glass transmits light of the right-handed circularly polarized light and a right eye glass transmits light of the left-handed circularly polarized light.
That is, the polarization directions of the projection lights output from the polarization controller are horizontally reversed due to reflection on the screen. For example, the right-handed circularly polarized light is reversed into the left-handed circularly polarized light, and the left-handed circularly polarized light is reversed into the right-handed circularly polarized light.
In this way, the projection light for the right-eye image that is reversed into the left-handed circularly polarized light enters the right eye of the viewer through the right eye glass of the polarization glasses (that transmits the light of the left-handed circularly polarized light). Further, the projection light for the left-eye image that is reversed into the right-handed circularly polarized light enters the left eye of the viewer through the left eye glass of the polarization glasses (that transmits the light of the right-handed circularly polarized light). Thus, the viewer can view a three-dimensional image by the parallax images of the right-eye image that enters the right eye and the left-eye image that enters the left eye.
On the other hand, in a case where the number of reflections is even, at a point of time when the projection lights enter the polarization glasses, the polarized lights of the respective projection lights for the right-eye image and the left-eye image output from the polarization controller are not horizontally reversed.
Thus, in a case where the polarization glasses are configured so that the left eye glass transmits the right-handed circularly polarized light and the right eye glass transmits the left-handed circularly polarized light, the projection light for the right-eye image enters the left eye and the projection light for the left-eye image enters the right eye, and thus, the viewer cannot view a correct three-dimensional image.
As described above, in a case where since respective polarization characteristics of the right eye glass and the left eye glass of the polarization glasses are fixed, the polarization directions of the left-eye image and the right-eye image do not correspond to transmission characteristics of the right eye glass and the left eye glass of the polarization glasses as the number of reflections of the projection lights is even or odd, the viewer cannot view a correct three-dimensional image.